Marine sanitary devices in particular and waste disposal systems in general have been proceeding through an evolutionary process for a number of years. The Environmental Protection Agency (EPA) has issued various specifications regarding requirements for processing liquid and solid human waste as set forth in 33 C.F.R. 159. Sewage or waste disposal basically requires that, under certain circumstances, substantially all of the solid waste must be removed from any liquid discharged from a vessel. An additional requirement of EPA is to reduce the fecal coliform bacteria to less than 200 per 100 milliliters. In many instances recirculation of the fluid, for example water, is desirable.
Separation of solid waste and collection can be accomplished in a variety of different well known manners. The difficulty resides in storage and disposal. Clearly improvements in this area are necessary particularly when stringent EPA sanitary regulations are taken into consideration and criteria such as size, cost and efficiency of operation are kept in mind.
Two effective systems are disclosed in commonly owned U.S. Pat. No. 4,393,524 and U.S. Pat. No. 4,433,443. In addition to the general concerns discussed above, certain specific applications raise other concerns. For example, certain uses might bring forth circumstances where filtered fluid can be again recontaminated by contacting separated waste material. This can occur when the system is adapted for use in a marine environment and the vessel is subjected to severe pitch and roll. Thus, optimum systems for that environment would desirably include means for directing the filtered fluid immediately away from an area where it might contact the separated solid waste and to an area of storage where it is isolated from the separated solid waste.
Additionally, in many environments, disposal of the filtered fluid from the system is denied either by legal requirements or otherwise. Thus, the system should be adapted for use as a completely closed system with the fluid continuously recirculating and stored after use. Thus the system should be versatile in that it can be used in areas which permits discharge of filtered fluid and in those areas which do not permit discharge of filtered fluid.